SEPARATION AND PURIFICATION TECHNOLOGY
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2022
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IF 9.136
Xing Zhang,Suhang Chen,Haidong Luo,Zhenhua Tang,Enzhou Liu,Zhao Qin,Kangzhen Xu
The rapid redox cycle of metal active sites and effective surface reactions are crucial factors to activate peroxymonosulfate (PMS) for environmental remediation. Herein, a novel F-g-C 3 N 4 /Mn x Co 3−x O 4 composite as high-efficient PMS activator was successfully constructed by a one-step hydrothermal method for the degradation of 1,1-diamino-2,2-dinitroethylene (FOX-7). It was discovered that F doping could narrow the band gap, and enhance the light absorption range and the separation of photogenerated electron-hole pairs. Among all samples, the catalytic activity of F-CN/MCO was higher than that of MCO and CN/MCO. This can be attributed to the unique materials morphology and the synergistic effect of photocatalytic and chemical catalytic driven PMS activation. Quenching experiments and electron paramagnetic resonance (EPR) proved that both radical and non-radical pathways are responsible for the degradation of FOX-7, and singlet oxygen ( 1 O 2 ) was identified as the predominant active species. Importantly, the synergy between Co 2+ /Co 3+ and Mn 2+ /Mn 3+ couples enhanced more electron transfer and better redox potential, thus greatly promoting the photocatalytic activation of PMS. This work provides a novel approach for designing efficient catalyst to promote the redox behavior of metal species in sulfate radical-based advanced oxidation processes.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2025
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IF 9.7
Jinqing Jiao,Hongjie Chi,Linsheng Xu,Xuqing Lang,Guangwen Zhang,Jing Xiong,Zhen Zhao,Chun Wang,Pengyu Cui,Yuechang Wei
Herein, we have elaborately designed and successfully fabricated the high-efficient hollow porous Mn x Co 3-x O 4 nanoreactors (MnCo-HPs) by optimizing the heating decomposition conditions of metal-organic frameworks Mn 3 [Co(CN) 6 ] 2 ·nH 2 O precursors with a nanocube-like structures. The diameter of the nanopores on the shells of MnCo-HPs is around 10.0 nm, which is beneficial for improving the diffusion of NO and O 2 into the hollow porous cage and enhancing the activation of NO to NO 2 . The feature of hollow porous structures can provide a larger surface area and more active sites, which can activate reaction gases and develop the contact efficiency between the nanoreactors and soot particles. The uniform distribution of Mn and Co species is conducive to the formation of coordination unsaturated defect sites and surface oxygen vacancies, resulting in the high catalytic activity for soot oxidation. As compared with conventional Mn x Co 3-x O 4 nanoparticles (MnCo-NPs) and hollow porous Co 3 O 4 nanoreactors (Co-HPs), MnCo-HPs possess the highest catalytic activity (T 50 = 341 °C), the lowest apparent activation energy (85.1 KJ mol −1 ) and excellent catalytic stability during soot oxidation. The catalytic activity of MnCo-HPs results from a perfect combination of the hollow porous structures, the strong interaction of manganese and cobalt oxide species, as well as the uniform distribution/accessibility of active sites. The related characterizations and density functional theory (DFT) calculations reveal that the active sites can decrease activation energy of O 2 and desorption energy of NO 2 , which is the crucial steps of NO 2 -assisted catalytic mechanism for soot oxidation. MnCo-HPs are promising candidates for the commercial soot oxidation. It highlights a promising way for the rationally design of high-performance non-noble metal catalysts for the removal of soot particles.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHINESE JOURNAL OF CATALYSIS
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2020
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IF 6.146
Chengxiang Shi,Sana Ullah,Ke Li,Wei Wang,Rongrong Zhang,Lun Pan,Xiangwen Zhang,Ji-Jun Zou
Spinel-type manganese-cobalt oxides have been regarded as important class of electrocatalysts for oxygen reduction reaction (ORR). However, they are usually synthesized through oxidation-precipitation under aqueous ammonia and then crystallization at high temperature (150–180 °C), which not only increases the energy consumption but also induces the growth of particles that is unfavorable for ORR. Herein, through a facile precipitation-dehydration method, ultrasmall spinel manganese-cobalt oxide nanoparticles (~5 nm) homogeneously dispersed on conductive carbon black (Mn x Co 3- x O 4 /C) were fabricated at low temperature (60 °C). And the bimetallic composite oxide (Mn 1.5 Co 1.5 O 4 /C) with cubic spinel structure and high Mn content exhibits remarkable enhancement of ORR activity and stability compared with single metal oxide (both Mn 3 O 4 /C and Co 3 O 4 /C). The essential reason for the enhancement of activity can be attributed to the presence of the mixed Mn 3+ and Mn 4+ cations in Mn 1.5 Co 1.5 O 4 /C. Moreover, the ORR activity of Mn 1.5 Co 1.5 O 4 /C is comparable to that of commercial 20 wt% Pt/C, and the relative current density only decreases 1.4% after 12 h test, exceeding that of Pt/C and most reported manganese-cobalt oxide electrocatalysts.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
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2022
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IF 8.047
Shaomian Liu,Yongjun Ji,Wenqing Xu,Jianling Zhang,Ruihuan Jiang,Liang Li,Lihua Jia,Ziyi Zhong,Guangwen Xu,Tingyu Zhu,Fabing Su
Developing efficient catalysts for low reaction-temperature catalytic reduction of NO by CO (CO–DeNO x ) is desirable but very challenging. Here, we report that hierarchically interconnected porous (HIP) Mn x Co 3- x O 4 spinels, synthesized by a facile citric acid-assisted sol–gel method, can act as highly efficient catalysts for CO–DeNO x . The obtained Mn 0.3 Co 2.7 O 4 displayed a much-enhanced catalytic performance with 87% NO removal at 100 °C and a wide active-temperature window (100–400 °C). Its superior activity stems from the following reasons: (i) the high-valence of Mn 3+ , Mn 4+ , and Co 3+ species in the Co–O–Mn structure enables the high catalytic activity and the effective redox-cycling of the Co 3+ and Co 2+ adsorption sites; (ii) the HIP structure can significantly enhance gas diffusion. This work offers an avenue to design metal oxide catalysts for CO–DeNO x by effectively controlling the doping metal concentration and oxidation states of the active components.
研究领域:
材料科学
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环境催化
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化学工程
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2018
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IF 11.698
Ke Li,Rongrong Zhang,Ruijie Gao,Guo-Qiang Shen,Lun Pan,Yunduo Yao,Kaihui Yu,Xiangwen Zhang,Ji-Jun Zou
Manganese-cobalt spinel oxides are considered as a class of promising and low-cost electrocatalysts for oxygen reduction reaction (ORR), whose performances largely depend on their electronic structures which can be effectively optimized by defect engineering. Herein, metal defects (manganese vacancies and cobalt vacancies, i.e. V Mn and V Co ) were in-situ introduced into spinel Mn x Co 3-x O 4 via a simple solvothermal treatment followed by thermal calcination. Mn-Co glycerolate precursors not only enable controllable synthesis of spinel oxides with variable metallic ratios, but also play a key role in constructing metal defected crystals for their lamellated structure. As a result of the formation rate difference between manganese and cobalt glycerolate, a unique Mn-enriched surface is formed, leading to the increase of highly active sites for ORR. Importantly, the presence of metal defects, confirmed by XRD (X-ray diffraction), element analysis and XAFS (X-ray absorption fine structure spectroscopy), leads to greatly increased electrical conductivity and O 2 adsorption ability, thus bringing about enhanced ORR activity. Especially, metal-defected Mn 1.5 Co 1.5 O 4 , with the optimal Mn/Co ratio, exhibits comparable activity and superior durability to those of the benchmark Pt/C in ORR and displays excellent discharge performance in Zn-air batteries for practical application. This work provides a new way to optimize the electrocatalytic performance of mixed metal spinel oxides via rational defect engineering.
研究领域:
材料科学
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电化学
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能源科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2021
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IF 13.273
Dan Li,Ziye Kang,Hao Sun,Ying Wang,Haiming Xie,Jia Liu,Jiefang Zhu
Although redox mediator (RM) strategy can decrease the overpotential in Li-O 2 batteries by tuning the electrochemical formation/degradation of Li 2 O 2 from the circumscribed surface pathway to the solution one, the redox shuttling causes an unexpected RM degradation and a continuous deterioration of Li anode, finally leading to a poor cyclability. This work presents the first report detailing the development of a novel Mn x Co 3-x O 4 -decorated separator for Li-LiI-O 2 batteries. Benefiting from the promotion effect of Mn x Co 3-x O 4 nanocages on I − /I 3 − and I 3 − /I 2 redox coupling, the cell with as-prepared separator maintains a low charge potential of ~3.3 V till the death of cell cycling. In addition, as-prepared separator can efficiently restrain the redox shuttling, leading to an obvious improvement on cycling stability for the cell. Moreover, the contributions of LiI to the battery performance and the operation mechanism are systematically investigated. These results present a promising progress in the development of multi-functional separator materials for RM-involved Li-O 2 batteries and the new design of hybrid energy storage device.
研究领域:
材料科学
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电化学
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能源存储技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）